"Primitive Machine" that Protected King's Chamber from Tomb Robbers Reconstructed

A system of grooves and blocks within the Great Pyramid that protected the King's Chamber from tomb robbers has been reconstructed using computer animation. Egyptologist Mark Lehner says that the system was sophisticated for its time calling it "a very primitive machine."

http://www.livescience.com/55347-primitive-machine-in-great-pyramid-protected-pharaoh.html